Hello, Let's put alsa-devel back to the CC... On Monday 25 January 2010 09:32:45 ext shariff wrote: > Hi Peter, > > 1) As we only have one Main MIC when I am recording in stereo mode by > specifying "-c 2", one channel is silent and one channel is recorded > properly. As it should. Just as a sidenote, I'm usually using -f dat for the format, which gives 48KHz, stereo 16LE > > 2) But still the recorded channel is noisy, how can I reduce the noise of > the recorded channel? Hmm, what kind of noise? How are you configuring the dai with the snd_soc_dai_set_fmt? For stereo it should be (if OMAP is slave, TWL is master): SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBM_CFM; For TDM mode (four channel): SND_SOC_DAIFMT_DSP_A | SND_SOC_DAIFMT_IB_NF | SND_SOC_DAIFMT_CBM_CFM; See omap3beagle.c how it is done. > > I have one more question. ( Regarding Audio path) > > ---> If I want to avoid that one channel silent, do I need to connect "SUB > MIC or AUXR"?( as these are connected right ADC). If you want audio data there, than yes you need another mic for the right channel. > ----> If I need to record 4 channel audio without any silent channel do I > need to connect digital microphones also? You can duplicate the channel 1 and 3 to channel 2 and 4, meaning that you route the ADCL and ADCR to these channels (TX1 and TX2 path are both analog). You can also hook up a stereo digital mic to the digimic1 interface, but remember, that the digimic needs 48KHz sampling rate. -- Péter > > Regards, > Shariff > > On Fri, Jan 22, 2010 at 6:29 PM, shariff > <shariffsinbox@xxxxxxxxx<mailto:shariffsinbox@xxxxxxxxx>> wrote: Hi Peter, > > Thank you very much for your suggestions. > > Regards, > Shariff > > > On Fri, Jan 22, 2010 at 6:11 PM, Peter Ujfalusi > <peter.ujfalusi@xxxxxxxxx<mailto:peter.ujfalusi@xxxxxxxxx>> wrote: Hello, > > On Friday 22 January 2010 11:57:23 ext shariff wrote: > > Hi all, > > > > I am working with OMAP3 based custom board that has twl4030 codec > > & using linux-2.6.29 kernel from opensource. > > This is kind of old... > > > I have some queries regarding Audio recording. > > > > Audio codec is connected to twl4030 as bellow > > > > TWL4030 > > > > |--------------------| > > | > > | |------ MAINMIC > > > > McBSP2 ------ |i2s/tdm | > > > > | ___________| > > > > --> One Analog MIC is connected to Main Mic and I am using Audio > > path not the Voice path. > > > > After selecting Main Mic through amixer control. > > > > and recording audio using "arecord -c 1 -r 8000 -f S16_LE -t > > wav -d 20 record-file.wav" > > The hardware should have been opened in stereo mode, since it is not > supporting the mono, you can verify it by appending -v to arecord and see > how the HW has been opened at the end. > > > --> Here record is successful but with lot of noise. > > > > 1) Can we record Mono(1 channel) through I2S from TWL4030 > > codec? > > The TWL codec "Audio" path is either stereo or 4 channel. > You need to record stereo/4 channel, and than extract/use the data from the > valid channel. > In case of Main mic it is the left channel, or Channel 1 or/and 2 > (depending on the routings) in four channel mode. > > > 2) To record stereo(2 channels), do we need two Mic's ? (i.e do > > I need Sub Mic also). > > No you don't need. The right channel will not contain valid data (most > likely it is going to be silent). > > You need to enable the Mic bias 1 for the main mic in your machine driver, > if you have not done that yet: > > static const struct snd_soc_dapm_widget your_widgets[] = { > ... > SND_SOC_DAPM_MIC("Your Mic", NULL), > ... > }; > > static const struct snd_soc_dapm_route your_audio_map[] = { > ... > {"MAINMIC", NULL, "Mic Bias 1"}, > {"Mic Bias 1", NULL, "Your Mic"}, > ... > }; > > I'm not sure about the state of the twl soc codec driver in 2.6.29, but my > guess is that it should work. > > Are there any capture routing option for TX1 path, which selects between > Analog and Digimic0? If there is than that has to be set to analog as > well. > > > Regards, > > Shariff > > -- > Péter > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
